Protecting device for mixing mills and the like



April 28, 1925. 1,535,392

w. s. ASHTON PROTECTING DEVICE FOR MIXING MILLS AND THE LIKE Filed 0%. 20, 1921 5 5" fig. W1H /2 m 5/95/7 ion Patented Apr. 28, 1925.

UNITED STATES PATENT. OFFICE.

WILLIAM S. ASHTON, F CHICOPEE FA LLS', MASSACHUSETTS, ASSIGNOR TO THE FISH RUBBER COMPANY, OF CHICOPEE FALLS, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

PROTECTING DEVICE FOR MIXING- MILLS AND THE LIKE.

Application filed December 20, 1921. Serial No. 528,643.

To an whom it may concern:

Be it known that I, WILLIAM S. AsHroN,

a citizen of the United States of America,

residin at Chicopee Falls, in the county of Hamp en and State of, Massachusetts,, have invented certain new and useful Im rovements in aProtecting Device for ixing Mills and the like, of which the following is a specification.

My invention relates to a combination adapted to collapse when subjected to a predetermined load and more particularly to a means for fireventing injury to cylinders of mixing mi s during the operation of the mills.

It is one ob'ect of my invention to provide simple, 0 cap and dependable means permitting the rotating cylinders of a mixing mill, which is adapted to condition a lastic material, to permit one to separate mm the other without injury when a dangerous pressure is exerted between them. It isanother object of my invention to provide means of this ty whereby the mill can be quickly put back lnto operation after the separation of the cylinders.

parallel c linders rotating toward one anno other. 7 ese cylinders are supported at their ends injournals, the journals of one the cylinders members forming collapsible units actmg against the cylinder journals to hold the same stationary during the ordinary'operation ofthe machine. Each umt t is customary to condition rubber stock by passing it between a pair of substantially.

comprises a pair of members adapted to telescope but ordinarily separated by a disk. One of the members is provided with a shoulder against which the disk is .positioned. The other member has an end acting against the other side of the disk, and is of such shape as to telescope within the first member if the disk is removed or sheared. When a dangerous pressure is exerted between the cylinders, it is transmitted through the cylinder journals to the telescopic members. As this pressure is exerted on the telescopic members the disk is sheared between them. After the disk has been sheared the members" telescope lon itudinally and thus allow the two cylinders to separate. My invention will now be described with reference to the accompanying drawings, in which,

Fig. 1 is an end view of a mixing mill partly broken away;

Fig. 2 is a front View thereof partly broken away and showing a partial section taken along the line 2-2 of Fig. 1;

Fig. 3 is a section of'one of the collapsible units,

Fig. 4 1s a plan view .of a disk forming an element of such unit;

Fig. 5 is a section taken along the line 5-5 of Fig. 4, and v v Fig. 6 is a section taken along the line 6-6 of Fig. 3 with the disk removed.

..A mixing mill in which my invention is incorporated is shown in Figs. 1 and 2 and comprises a main frame 10, yokes 12 secured to the main frame by means of bolts 13, and a pair of cylinders 14. and 15 rotatingly supported in the journa .16 and 17, which journals are suppor on the surfaces 18 of the frame. It i erally the practice to fix the position of .t e journals 16 and thus the position of roller 14 relative to the frame, and to move the cylinderv 15 transversel toward and away from the fixed oylindiar 14 by sliding the journals 17 alon the surfaces 18. The journals 17 are move transversely toward the journals 16 by the sliding back as a plastic substance 22 passes between the rollers.

If a hard substance is introduced between the rollers during the operation of the machine it is easily seen that if the journals 16 and 17 do not separate so as to provide sufficient space between the cylinders for the passage of this substance, a fracture of the cylinders will very likely occur. I therefore supply collapsible units or breaking combinations 23 (Fig. 1) between the journals 17 and parts 26 of the screws 20 which are in threaded relation with the frame 10. Upon the collapse of this combination the journals 17 slide awa from the journals 16 so as to permit the cy inder rolls to separate and allow the hard substance to passharmlessly between the rolls.

The breaking combination or collapsible unit 23 is shown in detail in Figs. 3, 4, 5 and 6. This combination comprises a casing 24, which is adapted to be rigidly bolted to the journal 17 by bolts 37 passing through belt holes 25, and a disk 34. The casing is provided with a central aperture 19, into which aperture extend the shoulders 28 and 30. The disk 34, which may be provided with a hole 36, fits within the aperture and rests against the shoulder 30 of the casing as shown in Fig. 3. The screw 20 may be provided with a lug 38 adapted to be inserted in the hole 36 of the disk 34. The screw is of suitable diameter to pass within shoulder 30, the purpose of which will later be described Clamp rings 39 (Figs. 1 and 2), hinged with respect to the frame on the lugs 41, which rings can' be 0 ened and closed by the screw 42, are use to clamp the cylinder controlling screws 20 in orderto prevent the turning of the same after they have been satisfactorily adjusted.

It will be noted that when pressure is exerted between the casings 24 and the screws 20, the disks separating these members will be subjected to a shearing stress since the edges of the members pressing on opposite sides of the disks are laterally offset from one another. Whena dangerous pressure 1s exerted between the cylinders it is transmitted through the journals to the casings 24. This pressure causes the disks to shear around circumferences indicated by AA (Fig. 3). ,Asthe disks shear, the casings 24 are pushed back so that they telescope with the screws 20, thusgallowing separation of the cylinders. The shoulder 28 serves to limit the passage of the screw 20 into the casing.

After the disks have collapsed to allow; the cylinder rolls to separate, 'the replace" ment of new disks in the combination to the machine again in running order is :a' simple matter. It is necessary only to run back the screws 20, clean out the broken disks from the apertures of the casings 24, place new disks in the casing apertures, and then advance the screws 20 until the parts resume their respective positions.

It frequently happens in practice that only one of the collapsible units breaks. This is especially true when a hard material passes between the cylinders near one end, for pactically the whole pressure will then be thrown against one unit. It is desirable that the collapsible units be designed so as to allow considerable separation of the cylinders even though only one unit collapses. In order to allow the cylinder 15 to move out of normal parallel relationship with the cylinder 16 due to the collapse of one of the breaking combinations, it is evident that the diameter of the screw 40 should be considerably smaller than the'diameter of the aperture, which will enclose a ortion of the screw upon the breakage oft e disk; in other words there should be a difference 44 of diameters between the screw and the aperture in order to allow the axis of the casing 24 to be turned at an angle with the axis of the screw when only one unit collapses and thecylinders assume a non-parallel relationship. The tapered sides 32 of the casing are sloped as shown in Fig. 3 in order to give clearance for the broken disk and prevent binding of the parts.

I have found that a crystalline metal such as machinedcast iron is well adapted as a metal for making the disks 34, since such material will shear without bendin even though the shearing forces are considerably offset from one another. The disks may be sliced from a machined cylindrical casting and thus I can save the expense of casting and machining the breakable parts so arately. Disks made in this manner are omogeneous as well as free from outside chilled surfaces and the pressure at which they will shear can be determined with accuracy.

Having thus described my invention I claim:

1. In a protective device for allowing separation of machine parts when an excessive pressure is exerted between them, an apertured removable member, a removable machined cast iron disk adapted to fit over the aperture, an adjusting screw laterally positioned with res set to the aperture and of suitable size and shape to enter. the aperture but prevented by the disk under ordinary workin conditions from entering the same, the dis bein adapted to be sheared between the outside edge of the laterally osi- .jtmed adjusting screw and the edge 0 the aperture of the removable member u on excessive strain being brou ht to bear l etween the machine parts, where y the sheared disk may be removed and-replaced without dis turbing the mounting of the machine parts. 9

2. In a roteeti've device for allowing septure but revented by the disk under ordiaration 0 machine arts when an excessive nary worEing conditlons from entering the 10 pressure is exerted tween them, an apersame, the disk being adapted to be sheared tured member movable with one of said between the outside edge of the laterally po- 1 parts, a removable disk adapted to fit over sitioned adjusting screw and the edge of the the aperture, an adjusting screw laterally aperture upon excessive strain being positioned with respect to the aperture and brought to bear between the machine arts; of suitable size and shape to enter the aper- WILLIAMS. ASH ON. 

